PROJECT SUMMARY There is an urgent need for the development of approaches to prevent cardiotoxicity in cancer patients being treated with anthracyclines, an important class of drugs in the treatment of cancer (e.g. doxorubicin). Anthracycline treatment-related cardiotoxicity is a major clinical problem that severely impacts patient care and also limits dose and usage. More than a quarter of patients who receive doxorubicin develop significant cardiac morbidity, and this effect has been shown to be dose dependent. In multiple preclinical studies, we and others have defined the therapeutic potential of low-dose exogenous carbon monoxide (CO) in anthracycline cardiotoxicity prevention, including protecting the cardiomyocyte from cell death and maintaining overall cardiovascular health. To date, inhaled CO gas (iCO) and CO bound to carrier molecules (CORMs) have been the modalities of choice in the majority of animal and in all the clinical studies carried out to study the potential benefit of CO. However, iCO and CORMS are not expected to be pharmaceutically acceptable and viable therapeutic options due to, with iCO, the risk of inadvertent exposure from the presence of compressed CO cylinders as well as difficulties in controlling dosing and, with CORMs, carrier molecule toxicology, stability, and CO release characteristics that have proven to be a substantial barrier to development. The objective of the proposed project is to investigate HBI-002, a novel oral CO drug product that was developed to enable the use of CO to prevent cardiotoxicity from anthracycline use. The safety and tolerability of CO has been demonstrated in eighteen successful Phase 1 and 2 clinical studies in other indications supported by well-defined preclinical data sets that led to approval by the FDA for human testing. HBI-002 comprises an oral formulation containing precise amounts of CO that are not bound to a carrier molecule (i.e. not a CORM) and efficiently absorbed from the gastrointestinal tract. Preclinical in vivo pharmacokinetic studies demonstrated proof-of-concept feasibility, tolerability, and bioavailability. The next step in development is to demonstrate that HBI-002 is effective in clinically relevant animal models of cardiotoxicity from anthracycline use as has been shown with other forms of CO and to better understand the potential mechanism(s) of action. Based upon the substantial literature of CO in preventing anthracycline cardiotoxicity, our central hypothesis that will be tested in this project is: HBI-002 will attenuate Doxorubicin- induced cardiotoxicity through stimulation of mitochondrial biogenesis.